NU coach Pat Fitzgerald and his players insist the transformation is the result of camaraderie, not new formations. They say the improvement came from summer bonding sessions, rather than chalk talk in the days leading to the Wildcats' stirring 23-13 victory over Vanderbilt on Saturday night at Ryan Field.

"The summer is a voluntary time," Fitzgerald said. "You can get your workout in and then go home. Or you can get your workout in and hang out, barbecue together. We have two beaches here on campus. Or go hang out at a Cubs or White Sox game.

"They did a lot of things together this summer that has forged the chemistry of the team."

OK, but how does chemistry help you hold Vanderbilt to 86 yards on 27 second-half plays? How does it result in fumble-forcing sacks by Quentin Williams and Tyler Scott?

"We have a great chemistry, and that's a huge advantage for us," Scott said. "It's great to have guys who communicate well because we are very close."

After getting gashed last season to the tune of 409.5 yards per game — 81st in the country — it was more of the same in NU's season opener at Syracuse.

The Wildcats got their wind back Saturday. They chased Jordan Rodgers, Aaron's brother, sacking him three times. And they held one of the SEC's top backs, Zac Stacy, to 36 net rushing yards on 13 carries.

"(The defense is) really tired of being the Achilles heal," Fitzgerald said. "They're human. Those guys are competitive and they want to be great. They hold themselves responsible. They are playing for each other."

And they're playing for NU's offense, which produced just six points during its first eight drives, excluding a clock killer before halftime.

"They saved our butts for a good part of the game," quarterback Trevor Siemian said.

Siemian took over for Kain Colter in the fourth quarter and led the Wildcats on two terrific drives, covering 159 yards on 23 plays. Then Colter sealed the victory with a 29-yard scamper.

"Colter is obviously the runner and 13 (Siemian) is the passer," Vanderbilt linebacker Chase Garnham said. "He did a better job than Colter, I thought. (But) Colter was pretty quick. He's nothing we haven't seen before, but he was pretty shifty — pretty quick."

It's fun for some fans to debate how Fitzgerald should handle his quarterbacks for NU's next challenge, Saturday against Boston College.

He'll stick with the current formula, thank you very much, considering it has produced victories over a rugged SEC foe and a Syracuse team that cranked out 455 yards of offense in a 13-point loss to USC.

"I wouldn't say it's like going to the bullpen," Fitzgerald said. "Maybe it's softball where you can re-enter (the game). We have two guys we believe we can win with, and that's a good problem."